Endotoxin is a lipopolysaccharide existing on the surface of the outer membrane of gram-negative bacteria and exhibits pyrogenicity. Endotoxin must be removed from pharmaceutically acceptable products.
Lipopolysaccharide endotoxin is not living bacteria and cannot be deactivated by common sterilization techniques, such as autoclaving. While gamma irradiation and dry heat sterilization techniques destroy endotoxin, these techniques may also destroy or damage many other components in a given composition. Therefore, many sterile products can contain significant levels of endotoxin unless the endotoxin is specifically removed or deactivated.
Current techniques employed in the pharmaceutical industry to remove endotoxin from biomaterials have one or more shortcomings. Size-separation techniques, such as gel permeation chromatography or ultrafiltration, provide less than acceptable results if the size of biomaterial is close to the size of endotoxin present in the biomaterial. Other techniques, such as absorption techniques, absorb endotoxin into one or more absorbents. However, if the endotoxin has a greater affinity for the biomaterial than the one or more absorbents, unacceptable separation results.
There exists a need in the art of effective methods of reducing endotoxins in chitosan and products containing chitosan.